Crushers and grinding disks therefor



June 13, 1961 H. A. MERGES CRUSHERS AND GRINDING DISKS THEREFOR Filed March 20, 1959 3 Sheets-Sheet l INVENTOR. HEEBEETA. MEEGES BY {I Mm June 13, 1961 H. A. MERGES 2,988,290

CRUSHERS AND GRINDING DISKS THEREFOR 3 Sheets-Sheet 2 Filed March 20, 1959 22 I5 F77. 5 2 FY1 1.35 26 f6 29 25 23 ,7 f 7 A -14 INVENTOR. HERBERT A. M52655 22 FIE .12 BY June 13, 1961 H. A. MERGES CRUSHERS AND GRINDING DISKS THEREFOR 3 Sheets-Sheet 3 Filed March 20, 1959 INVENTOR. HERBERT/1. MEQGES United States Patent a ,CRUSHERS AND GRINDING DISKS THEREFOR The present invention relates to crushers in general, and more particularly to a combined coarse crusher and fine grinder of the type comprising a pair of grinding disks with alternating circularly arranged concentric intermeshing groups of teeth on their adjacent working end surfaces. The invention also relates to improved crushing and grinding disks for use in such apparatus. The crusher of this invention is particularly suited for comminution of highly elastic and stringy materials, such as rubber waste and the like.

Previously proposed crushers of this character utilized a pair of disks with a great variety of specifically formed teeth of varying sizes which were arranged in concentric circles and whose purpose was to subject the treated material to a comminuting action. For example, it is already known to utilize teeth of substantially trapeziform cross-sectional contour whose magnitude decreases from the centers toward the peripheries of both grinding and crushing disks, and whose number increases in each circular group of teeth of progressively increasing diameter. When the circular groups of teeth on both grinding disks are comparatively deeply intermeshed with each other, i.e. when the axial distance between the disks is rather small, the teeth perform a cutting and shearing action upon the particles of treated material. On the other hand, when the axial distance between the disks is increased, their teeth perform a kneading or stuffing action.

As above stated, the crushers of this general character are particularly suited for use as a means for com minuting stringy or tough and elastic materials. However, when it is desired to comminute highly elastic materials, such as waste particles of vulcanized rubber and the like, the cutting or shearing action of adjacent circular groups of teeth in known crushers is insufficient to reduce the size of introduced material into particles smaller than a product of sandy or gritty consistency, also known as rubber meal. Thus, such presently known crushers cannot be utilized for the comminution of rubber meal into a product of extremely fine mesh and which, heretofore, has been produced by transferring the partially comminuted product obtained by passing rubber waste through known crushers of the above described characteristics into a grinding mill utilizing rotating rollers which subject the sandy or gritty material to frictional forces sufficient to further comminute same into one of flourlike consistency. The two-stage treatment in two diiferent machines has a number of serious disadvantages,

such as considerable losses in time, complications arising an apparatus of the above outlined characteristics which is particularly suitable for transformation of relatively coarse rubber waste and other elastic and tough materials into a product finer than that known in the trade as rubber meal.

A further object of the present invention is to provide a combined crushing and grinding apparatus which is ice capable of subjecting highly elastic and other tough materials to a crushing action and immediately thereafter to a fine grinding action comparable to that of known grinding mills.

A still further object of the instant invention is to provide improved crushing and grinding disks for use in apparatus of the above described type whose teeth are so formed as to bring about an exceptionally economical and very fine grinding and crushing action upon the material passing therethrough while requiring comparatively small forces for the rotation of at least one disk.

The above and certain other objects of the invention are attained by the provision of two grinding disks at least one of which is driven with respect to the other disk, both grinding disks having adjacent end surfaces each integrally formed with a number of concentrically arranged circular groups of teeth thereon, and at least two outermost circular groups of teeth on at least one of the disks, i.e. on the rotary disk, tapering at least in that direction in which the rotary disk is driven. Thus, if only one of two cooperating disks is rotated when the apparatus in which the disks are installed is in operation, at least but preferably more than two outermost circular groups of teeth on the rotary disk may be of e.g. substantially triangular or tear shape with the pointed end portions of such teeth oriented in the circumferential direction in which the disk rotates. A concentric outermost zone constituting at least one-fourth but preferably more than onethird of the working end surface on the rotary disk, adjacent to the latters periphery and measured in the radial direction thereof, may be integrally formed with several circular groups of teeth which taper at least in that direction in which the disk rotates. It is equally within the scope of my invention to cover the aforementioned outermost zone of the end surface on a rotary disk with several circular groups of teeth which taper in two circumferential directions, i.e. in and contrary to the direction in which the disk rotates. For example, such teeth may be of semilenticular, ellipsoidal or rhomboidal shape. It is further possible to progressively reduce the height of teeth in the outermost zone of the working surface at least in the direction in which the disk rotates, i.e. when the teeth are of triangular or drop shape, or to reduce the height of teeth in the outermost circular group or groups in both directions from their respective centers, i.e. when the teeth are of rhomboidal, semi-lenticular or ellipsoidal shape. The exact width of the outermost zone of the working surface on a grinding disk which is formed with such teeth depends upon the nature of treated material and also upon the desired fineness, i.e. mesh, of the ultimate product.

The concentric intermediate zone of the working surface on at least one of the cooperating disks may comprise concentric circularly arranged groups of teeth of, for example, trapeziform constant cross-sectional contour which may be formed as arcuate bodies with a curvature similar to that of the circular group in which the respective teeth are located. For example, the width of the intermediate zone may constitute between about onefourth and one-third of the width of the entire working surface as measured in the radial direction of a so-constructed crushing and grinding disk.

The innermost concentric groups of teeth are preferably arranged in at least two but usually three or four concentric circular rows. These teeth are normally larger than those in the concentric intermediate and outermost zones of the working end surface and are preferably of arcuate shape with a curvature conforming to the curvature of circular groups in which they are arranged. It is also preferred to form at least two innermost groups of teeth on the rotary disk. in such manner that they diminish in height and width in the direction opposed to that in which the disk rotates. The other disk may be formed with at least two innermost groups of teeth which taper in the opposed circumferential direction, i.e. in-the direction in which the rotary disk is rotatedp The width of this innermost concentric zone on each disk, too, preferably approximates between about one-fourth and one-third of the entire working end surface.

The teeth on the working end surfaces of two cooperating grindingdisks may be of identical but also of widely different configuration. One of the disks may be formed with more circular groups of teeth than the other disk. The magnitude of teeth normally decreases and their number in adjacent circular groups normally increases from the center toward the periphery of the respective disk.

Only one of two cooperating grinding disks may be driven or, if desired, both disks may be driven in opposing directions at identical or different angular speeds. It is also possible to drive both disks in the same direction but at different angular speeds.

The disks are built into a housing which may be formed with a hopper for introducing the material into a concentric opening formed in the disks and, when at least one of the disks is rotated, the developing centrifugal force'causes the particles of introduced material, e.g. waste particles of vulcanized rubber or the like to enter between the innermost circular groups of teeth and to be thereupon advanced by centrifugal force and by the teeth themselves toward the peripheries of the disks wherefrom they. emerge as a finely comminuated product of flour-like consistency.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is an axial section through one half of a somewhat schematically illustrated combined crusher and grinder showing two cooperating crushing and grinding disks in full lines and certain other component parts of they apparatus in phantom lines;

FIG. 2 is a fragmentary perspective view of a crushing and grinding disk constructed in accordance with my invention;

FIG. 3 is a fragmentary top plan view of a modified disk formed with teeth in the outermost or peripheral zone of its working surface slightly different from those of the disk shown in FIG. 2;

FIGS. 4 and 5 are similar fragmentary top plan views of two additional modifications, the disks therein shown having working surfaces with outermost or peripheral zones embodying teeth different from those in the peripheral zones of working surfaces on the disk illustrated in FIGS. 2 and 3;

FIGS. 6 and 7 are enlarged side elevational and top plan views, respectively, of a tooth or grinding element similar to those utilized in the innermost zones of working surfaces on the crushing and grinding disks shown in FIGS. 2 to 5;

FIGS. 8 and 9 are enlarged side elevational and top plan views, respectively, of a tooth similar to those utilized in the intermediate zones of working surfaces on the crushing and grinding disks shown in FIGS. 2 to 5;

FIGS. 10 and 11 are enlarged side elevational and top plan views, respectively, of a tooth similar to those utilized in the outermost or peripheral zone of the working surface on the crushing and grinding disk shown in FIG. 2; 7

FIGS. 12 and 13 are enlarged side elevational and top plan views, respectively, of a tooth or cutting element utilized in the peripheral zone of the working surface on the disk shown in FIG. 3;

FIGS; '14 and 15 are enlarged side elevational and top plan views, respectively, of a tooth similar to those utilizedin the peripheral zone of the working surface on the crushing and grinding disk shown in FIG. 4;

FIGS. 16 and 17 are enlarged side elevational and top 4 plan views, respectively, of a tooth similar to those utilized in the peripheral zone of the working surface of the disk shown in FIG. 5 and FIG. 18 illustrates in top plan view one half of a stationary disk with a reduced number of teeth on its working surface, and one half of a rotary disk with a complementary set of teeth.

The combined crusher and grinder 1 illustrated in FIG. 1 comprises a movable or rotary crushing and grinding disk 2 having an upwardly turned working end surface formed with three different types of teeth 3, 4, 5, respectively. These teeth will be described in full detail in connection with FIGS. 2 to 17. Disk 2 is formed with a concentric opening which receives the preferably noncircular end 7 of a driving shaft 6, the latter being fixed to the member 2 by a nut S or the like. A portion of the crushers housing which surrounds the disk 2 and the shaft 6 is shown in phantom lines and is identified by reference numeral 1a.

The complementary or stationary crushing and grinding disk 9 is connected to the cover or lid 10 of apparatus 1 by threaded bolts 11 or the like. The lid 10 and the hopper 12, which latter supplies the material to be comminuted into the concentric opening surrounded by the teeth of disks 2 and 9, are shown in phantom lines.

The combined crusher and grinder I of FIG. 1 is particularly suitable for crushing and grinding of rubber waste into a product finer than rubber meal, but it will be readily understood that its use is not limited exclusively to the comminution of such materials. The waste or scrap entering the opening in the center of rotary disk 2 is set in motion and, owing to the centrifugal force, is caused to enter between the alternating circularly arranged inner most concentric groups of teeth 3, 3' on the adjacent working end surfaces of disks 2 and 9, respecttively.

The teeth 30f rotary disk 2 taper in a direction opposed to that in which the disk rotates while the innermost teeth 3' of the stationary disk 9 taper in the opposing direction, i.e. in the direction in which the disk 2 rotates. In the construction represented in FIG. 1, disks 2 and 9 are formed with three concentric circular groups of teeth 3, 3', respectively, the groups of teeth 3 alternating with and extending between the groups of teeth 3, and the number of teeth 3, 3' in each row or group of progressiyely greater diameter increasing with respect to that in the row or group surrounded thereby. During the rotation of disk 2, teeth 3 and 3 engage the waste particles and their cutting edges, operating in the manner of scissors, bring about a first reduction in the size of material passing therethrough.

Underthe influence of centrifugal force, the partially comminuated material passes beyond the outermost circular group of teeth 3 on disk 9 and enters between the teeth 4', 4' in the intermediate zones of working surfaces on grinding disks 2 and 9, respectively. Teeth 4, 4' are smaller and more numerous than the teeth 3, 3', i.e. each circularly arranged concentric group of teeth in the intermediate zones may be formed with progressively increasing numbers of teeth 4, 4', for example, proportionally with the increase in diameters of their circles. Teeth 4, 4' bring about a further reduction in the magnitude of partially comminuted particles discharged through the outermost circular group of teeth 3', and the so-reduced particles are thereupon caused by centrifugal force to enter between the outermost or peripheral zones of working end surfaces on the disks 2 and 9, i.e. between the concentric circularly arranged groups of teeth 5, 5, respectively. In accordance with an important feature of the present invention, the teeth 5, 5' taper at least in that circumferential direction in which the disk 2 rotates, or, as will be described in connection with FIGS. 2 and 5, these teeth may taper in both circumferential directions, i.e. clockwise and anti-clockwise. Each of circularly arranged concentric groups 5, 5' contains a large number of teeth which subject the twice-reduced particles to a final comminuting action analogous to the rubbing or grinding action of known friction rollers. If rubber scrap is passed between the working end surfaces of disks 2 and 9, the final product emerging beyond the outermost circular row or group of teeth 5' is a finely ground meal of uniform mesh consisting of very soft elastic particles.

Referring now to FIG. 2, there is shown a segmental portion of a rotary disk 2a comprising three circularly arranged concentric groups of teeth 13 which project beyond the innermost zone of its working end surface and which correspond to members 3 on the disk 2 shown in FIG. 1. Each tooth 13 tapers in a direction opposed to that, indicated by arrow 14, in which the disk 2a rotates. A portion 13A of each tooth 13, adjacent to the latters front end surface 17, is of trapeziform cross-sectional contour; it is also bounded by a top surface 15 and by a pair of inclined side surfaces 16. The roughly horn-shaped rear portion 13B of each tooth 13 is arcuate, its curvature conforming to the curvature of the broken-line circle 19 which is concentric with the disk 2a. Portion 13B tapers in width and diminishes in height rearwardly in the circumferential direction opposed to that indicated by arrow 14. As can be observed in FIG. 2, the overall size of teeth 13 decreases as the diameters of circles in which the successive rows or groups of said teeth arearranged increase, and each row of progressively increasing diameter comprises a larger number of teeth 13. As before stated, these teeth bring about a partial or preliminary comminution of treated material.

The intermediate zone of the working surface on disk 2a is formed with four circularly arranged concentric rows of teeth 20 whose function is to further reduce the size of partially comminuted material. Each tooth. 20 resembles in top plan view a finite length of an annular band, i.e. its horizontal projection or outline is of uniform width and of a curvature corresponding to that of the circular row or group in which the selected tooth 20 is located. Each tooth 20 is of trapeziform constant cross-sectional contour and is bounded by a flat top surface, by two elongated side surfaces converging toward each other in a direction away from the disk 2a, and by a pair of inclined end surfaces also converging in a direction away from the disk 2a.

The outermost or peripheral zone of the working end surface on disk 2a is formed with five concentric rows or groups of progressively diminishing teeth 21 whose function is to further reduce the size of twice-ground material after the latter has already passed between the teeth 13 and 20 in the two inner zones of the working end surface on disk 2a. In cooperation with the complementary teeth of the non-represented stationary disk, members 21 then perform a fine grinding action upon the treated material. The shape of each tooth 21 approximates that. of a halved lens, i.e. its central portion adjacent to the working end surface of disk 2a is of maximum height and widthwhich thereupon decrease toward both ends of tooth21. Thus, it can be said that each semi-lenticular tooth 21 tapers from its center toward its longitudinal ends, that is, in circumferential directions identical with, and opposed to, that indicated by arrow 14.

FIG. 3 illustrates a crushing and grinding disk 2b which is nearly identical with the disk 2:: save for the configurationof teeth 22. in the outermost or peripheral zone of its working'end surface. It comprises three concentric circular rows or groupsof relatively large teeth I3, three concentric circular rows or groups of medium-sized teeth 20 surrounding the teeth 13, and five rows or groups of comparatively small teeth 22 also disposed in concentric circles about the teeth 20. Each tooth 22 is substantially dropor tear-shaped and tapers in height and width in the circumferential direction of arrow 14. Also, the size of teeth 22' decreases as the diameters of their rows increase, i.e. in a direction toward the periphery of disk 25.

The disk 20 of FIG. 4, too, is almost identical with members 2a and 217 save for the configuration of teeth 23 in the peripheral zone of its working end surface. The outline of each tooth 23 is similar to that of an acute triangle whose longer sides taper in the circumferential direction of arrow 14. The height of teeth 13, too, decreases in the direction of said arrow.

The substantially rhomboidal teeth 24 in the outermost zone of the working end surface on the disk 2d shown in FIG. 5 are quite similar to teeth 21 illustrated in FIG. 2, i.e. they diminish in height and width from the centers toward the respective ends thereof.

FIGS. 6 and 7 illustrate on alarger scale and in two diiferent views one of the teeth 13 already described in connection with FIG. 2. The front end surfaces 17 on the teeth 13 of two cooperating disks are turned in op posed circumferential directions, i.e. in the direction, and counter to that, in which at least one of the disks rotates or, if both disks rotate at different speeds, in the direction of, and counter to that in which, the more rapidly driven disk rotates. When only one of the disks is rotated, the front end surfaces 17 of the teeth 13 thereon face the direction of rotation. Due to such arrangement, and assuming that the tooth 13 shown in FIGS. 6 and 7 forms part of a rotary crushing and grinding disk, the inclined cutting edges 25 at the lateral ends of its front end surface 17 cooperates with similar cutting edges of the non-represented fixed disk and subject the advancing particles of rubber or any other treated material to a shearing action. After passing the cutting edges 25 and similar edges on the innermost teeth of the fixed disk, the partially comminuted material is entrained into the space adjacent to the rear portions 13B of teeth 13 to thereupon pass be tween the individual components of successive concentric circular groups or rows of teeth 13 toward the innermost row of teeth 21 one of which is shown on a larger scale and in two different views in FIGS. 8 and 9. As fully described in connection with FIGS. 2 to 5, teeth 20 of say rotary disks 2a-2d further comminu'te the partially crushed material which is thereupon caused by centrifugal force to enter, for example, between the outermost teeth 21 of the disk 2a. One tooth 21 is shown on a larger scale and in two different views in FIGS. 10 and 11. It resembles the shape of a halved lens whose semicircular edge is partially blunted to form an arcuate top surface 26;

FIGS. 12 and 13 show on a larger scale and in two different views one of the teeth 22 already described in connection with FIG. 3. The tooth 22 therein shown is tear-shaped and, when forming part of a-rotary disk, its pointed end 27 is turned in the direction in which the disk rotates. Its rounded rear end 28 points in the opposing direction.

The substantially pyramidal tooth 23, shown one larger scale and in two different views in FIGS. 14 and 15, is quite similar tomembers 22. Its outline approximates that of an acute triangle (see also FIG. 4) and, due to the provision of a comparatively narrow top surface 29 thereon, the tooth 23 is of trapeziform cross-sectional contour. Surface 29 is formed by slightly blunting the upper edge of the tooth 23.

FIGS. 16 and 17 illustrate on an enlarged scale and in two different views one of the teeth 24 previously described in connection with FIG. 5. The outline of hori zontal'projection of member 24 iso'f rhomboidal contour; i.e. it deviates only slightly from that of members 21 shownin FIGS. 2, l0 and 11.

FIG; 18 illustrates a rotarydisk'iil' practically'identical with the-member 2b show'ninFIG. 3 with theexceptiori that it comprises only two rows of teeth 13, two rows of teeth 20, and only three rows of teeth 22. Member 31 rotates in the direction of arrow 32 relative to the fixed grinding disk 30 which latter comprises analogous concentric rows of teeth 13', 20' and 22', respectively, which 7 alternate and cooperate with concentric rows of teeth 13, 20 and 22 in that order.

Whenthe complementary grinding disks are in operation, i.e. when at least one thereof rotates, the comparatively small teeth (see FIGS. 10 to 17) in the outermost zones of their working surfaces perform not only a fine crushing but also an extremely fine grinding action upon the partially comminuated material. By suitable axial spacing of the disks with respect to each other, i.e. by deeper or shallower intermeshing of concentric groups of teeth in the outermost zones of their working end surfaces, the action of teeth in the outermost zones upon the particles of treated material is similar to that of known friction rollers. In this manner, a granulate or gritty substance may be comminuated into a soft powder of mealy consistency. Thus, the disks of above-described construction," and more particularly the combined crushers and grinders utilizing such disks, are particularly suited for the manufacture and simultaneous further comminution of rubber meal and of many other materials of like consistency which are characterized by very fine mesh as well as by looseness and softness of their particles. The consistency of final products obtained by the utilization of my improved apparatus is similar to that of pigments utilized in the manufacture of paints, or to that of fillers utilized for incorporation into many types of plastic materials.

The invention, is, of course, not limited to the specific embodiments disclosed and illustrated but may be realized in many additional modifications and adaptations without departing from the spirit and scope of the appended claims. Thus, the cooperating disks of my improved apparatus may be rotated in opposing directions at identical or different angular speeds or, as described in connection with FIGS. 1 and 18, one of the disks may remain stationary while the other rotates with respect thereto. Finall'y, both disks may rotate in the same direction but at different angular speeds.

It is also pmsible to form one of the cooperating disks with teeth of uniform configuration though not necessarily of the same size as long as such teeth are capable of cooperating with the teeth on the other disk. If only one of the disks rotates, such uniformly configurated teeth are then formed on the fixed member. For example, all teeth on one of the disks may be of constant trapeziform cross-sectional contour, or they may be ,7

formed as the member 13 shown in FIGS. 6 and 7.

Also, the teeth in the corresponding zones of the working endsurfaces on both disks need not be of identical configuration as long as they can cooperate with the complementary teeth in the adjacent circular rows of teeth on the other disk.

What I claim is:

1. In a combined crushing and grinding apparatus, in combination: a first and a second disk each having a periphery and an end surface, and each comprising a plurality of concentric circularly arranged groups of teeth integral with and projecting beyond its end surface, the groups of teeth on said first disk alternating with and extending between the groups of teeth on said second disk; and means for rotating said first disk, the end surface of said first disk having a concentric outermost zone adjacent to the periphery of said first disk and a second zone surrounded by said outermost zone, the teeth integral with said outermost zone arranged in at least two groups and at least a portion of each tooth in said outer most zone diminishing in height and in width at least in that circumferential direction in which the first disk rotates, the teeth integral with said second zone arranged in a plurality of groups and at least one group of teeth in said second zone adjacent to said outermost zone being of constant trapeziform 'cross-sectional contour.

,2. The structure as set forth ,inclaim 1, whereinthe teeth in said outermost zone are of tear shape, each tear shaped tooth having a pointed end oriented in the circumferential direction in which said first disk rotates.

3. The structure as set forth in claim 1, wherein the teeth in said outermost zoneare of triangular outline, each said last mentioned tooth having an acute angled end oriented in the circumferential direction in which said first disk rotates.

4. The structure as set forth in claim 1, wherein the teeth in said outermost zone diminish in height and in width in two opposing circumferential directions, one of said opposing directions being the direction in which said first disk rotates.

5. The structure as set forth in claim 4, wherein said last mentioned teeth are of semi-lenticular shape, each semi-lenticularly shaped tooth having a central portionof maximum height and width and diminishing in height and in width from its central portion in the circumferential direction of and counter to that in which the first disk rotates.

6. The structure as set forth in claim 4, wherein said last mentioned teeth are of rhomboidal shape, each rhomboidally shaped tooth having a central portion of maximum height and width and diminishing in height and in Width from its central portion in the circumferential direction of and counter to that in which the first disk rotates. I

7. The structure as set forth in claim 1, wherein the radial width of said outermost zone equals between about one-third and one-fourth of the radius of said first disk.

8. The structure as set forth in claim 1, wherein said second zone consists of a cencentric intermediate zone adjacent to said outermost zone and of an innermost zone surrounded by said intermediate zone, the teeth of constant trapeziform cross-sectional contour integral with said intermediate zone and the teeth integral with said inner- 'most zone arranged in at least two groups, each said last mentioned tooth diminishing at least in width in a direction counter to that in which the first disk rotates.

9. The structure as set forth in claim 1, wherein at least the teeth which are integral with said second zone are of arcuate shape and of a curvature corresponding to the curvature of the respective group.

10. The structure as set forth in claim 1, wherein the end surface of said second disk has a concentric outermost zone adjacent to the periphery of said second disk, the teeth integral with said last mentioned outermost zone arranged in at least two groups and each said last mentioned tooth having at least a portion diminishing in height and in width in a circumferential direction counter to that in which said first disk rotates.

11. The structure as set forth in claim 1, wherein the teeth integral with the end surface of said second disk are of trapeziform cross-sectional con-tour.

References Cited in the file of this patent UNITED STATES PATENTS 212,838 Cutler Mar. 4, 1879 877,640 Gent Jan. 28, 1908 1,653,472 Scherbaum Dec. 20, 1927 1,676,663 Nicholls July 10, 1928 2,226,429 Hall Dec. 24, 1940 2,716,926 Armstrong Sept. 6, 1955 FOREIGN PATENTS 316,706 Italy Apr. 13, 1934 468,433 Great Britain June 29, 1937 574,508 Germany Apr. 13, 1933 

